Check not to insert nullptr to HeapHashSet<WeakMember>

third_party/WebKit/Source/platform/fonts/FontCache.cpp

 /*
  * Copyright (C) 2006, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 408 matching lines @@
 static bool invalidateFontCache = false;
 
 HeapHashSet<WeakMember<FontCacheClient>>& fontCacheClients() {
   DEFINE_STATIC_LOCAL(HeapHashSet<WeakMember<FontCacheClient>>, clients,
                       (new HeapHashSet<WeakMember<FontCacheClient>>));
   invalidateFontCache = true;
   return clients;
 }
 
 void FontCache::addClient(FontCacheClient* client) {
+  CHECK(client);
   ASSERT(!fontCacheClients().contains(client));
   fontCacheClients().insert(client);
 }
 
 static unsigned short gGeneration = 0;
 
 unsigned short FontCache::generation() {
   return gGeneration;
 }
 
@@ skipping 63 matching lines @@
   for (iter = gFallbackListShaperCache->begin();
        iter != gFallbackListShaperCache->end(); ++iter) {
     shapeResultCacheSize += iter->value->byteSize();
   }
   dump->AddScalar("size", "bytes", shapeResultCacheSize);
   memoryDump->AddSuballocation(dump->guid(),
                                WTF::Partitions::kAllocatedObjectPoolName);
 }
 
 }  // namespace blink